1. Field of the Invention
This invention relates generally to the field of internal combustion engines, and more particularly to two-stroke internal combustion engines.
2. Description of the Prior Art
U.S. Pat. No. 1,292,322 is directed to a water cooled two cycle gas engine provided with a dual walled cylinder having a lower, rotatably mounted perforated valve member for gas entry and accuated by a first cam and spring/rocker arm arrangement. Gases exhaust through an upper reciprocating sleeve valve member controlled by a cam movably connected to the shaft to the cylinder's piston connecting rod is also connected.
U.S. Pat. No. 1,540,286 relates to an internal combustion piston engine provided with exhaust valves located in the upper portion of the cylinder. The engine is also provided with either a rotary gas inlet or a crankcase gas inlet valve communicating with a crankcase gas pressuring chamber.
U.S. Pat. No. 2,337,245, discloses an internal combustion engine of the two stroke type having a set of gas inlet ports at one end of the cylinder and a set of gas exhaust ports at the other cylinder end. Each set of gas ports is opened and closed by means of a separate reciprocating piston which is positioned in the cylinder.
U.S. Pat. No. 2,516,708 relates to a single-acting two-stroke cyclic internal combustion engine having an associated air scavenging chamber adjacent to the gas inlet end of the cylinder.
U.S. Pat. No. 2,572,768 also relates to a two-stroke internal combustion engine having gas inlet ports providing swirling motion by tangential gas injection arrangements.
U.S. Pat. No. 2,316,790 relates to an internal combustion engine having a variable compression ratio which is provided by an auxiliary piston which reciprocates in synchronism with the working piston and functions to open and close valve ports of the engine and by a mechanism for ranging the stroke of the auxiliary piston.
U.S. Pat. No. 3,971,297 relates to a two cycle engine with three peripheral, oppositely displaced by-passes about the piston, to increase the breathing of the engine by-passing virtually the entire perimeter of the piston.
U.S. Pat. No. 4,004,557 discloses a piston-cylinder assembly having a cup-like upper extension of the piston, and a plurality of vertical passages between the crankcase and the cylinder.
U.S. Pat. No. 4,066,050 relates to two stroke internal combustion engines having a plurality of transfer ports controlled by the movement of the piston wherein some, but not all, of the transfer ports are provided with pressure-responsive non-return valves which are slightly biased toward the closed position, to restrict gas flow through those passages under predetermined engine conditions.
U.S. Pat. No. 4,359,017 relates to an internal combustion engine having diametrically opposed, co-axial cylinders, in each of which a piston in housed.
Japanese Patent Publication No. 57-159,918 relates to two cylinder engines wherein the connecting rod is cooled and lubricated by means of openings in the non-thrusting section of a piston and by providing an auxiliary scavenging passage which connects the openings to a scavenging passage in the process of scavenging.
British Pat. No. 362,453 relates to a two stroke compression ignition internal combustion engine.